This application relates to and claims priority from Japanese Patent Application No. 11-114413 filed on Apr. 22, 1999.
1. Field of the Invention
The present invention relates generally to refrigeration cycles, and particularly to a leakage restriction device for a refrigeration cycle. The leakage restriction device has plural leakage restriction members disposed in a pipe connection portion of the refrigeration cycle for restricting refrigerant flowing through the refrigeration cycle from leaking into atmospheric air.
2. Related Art
Conventionally, a leakage restriction device for a refrigeration cycle has a rubber gasket such as an O-ring disposed in a pipe connection portion of the refrigeration cycle. The rubber gasket prevents refrigerant flowing through the refrigeration cycle from leaking into atmospheric air from the pipe connection portion. The rubber gasket is made of rubber to facilitate assemble and service of the gasket, or is made of rubber and metal or rubber and resin.
Recently, environmental protection is emphasized globally, and an amount of refrigerant gas such as chlorofluorocarbon and carbon dioxide leaking into atmospheric air from a refrigeration cycle is urged to be reduced. To provide a solution for this demand, lowering a gas permeability of the rubber gasket has been studied to restrict refrigerant gas from passing through the rubber gasket to leak into atmospheric air.
However, when a gas permeability of the rubber gasket is lowered to further restrict refrigerant gas from leaking into atmospheric air, a blistering-resistance of the rubber gasket for restricting a blister from being formed in the rubber gasket may be lowered. That is, when the gas permeability of the rubber gasket is lowered, refrigerant gas having entered the rubber gasket when atmospheric air surrounding the rubber gasket has a relatively high pressure may not be drained from the rubber gasket even when the pressure of the atmospheric air is decreased. Therefore, refrigerant gas having a pressure higher than that of the atmospheric air may stay inside the rubber gasket and cause a blister or a crack in the rubber gasket. Thus, it is difficult to provide a rubber gasket which sufficiently restricts refrigerant from leaking into atmospheric air while restricting a blister from being formed therein.
In view of the foregoing problems, it is an object of the present invention to provide a leakage restriction device for a refrigeration cycle having plural leakage restriction members, which restricts refrigerant flowing through the refrigeration cycle from leaking into air while restricting the leakage restriction members from having a blister.
According to the present invention, a leakage restriction device for a refrigeration cycle through which refrigerant flows has a first leakage restriction member and a second leakage restriction member. The refrigeration cycle has a pipe connection portion at which refrigerant pipes are connected. The pipe connection portion is disposed in an air. The first leakage restriction member is disposed on an air side in the pipe connection portion for restricting refrigerant from leaking into atmospheric air. The second leakage restriction member is disposed on a refrigerant side in the pipe connection portion for restricting refrigerant from leaking into atmospheric air. The first leakage restriction member has a gas permeability lower than that of the second leakage restriction member, and has a blistering-resistance which is inferior to that of the second leakage restriction member.
Since the first leakage restriction member has a relatively low gas permeability, refrigerant is restricted from leaking into the air through the first leakage restriction member. Since the second leakage restriction has a relatively high blistering-resistance, the second leakage restriction does not form a blister even when a pressure of refrigerant is rapidly reduced. Further, a pressure of refrigerant between the first and second leakage restriction members does not change rapidly even when a pressure of refrigerant at a refrigerant side of the second leakage restriction member is rapidly reduced. Therefore, even when the pressure of refrigerant is rapidly reduced, a blister is not formed in the first leakage restriction member. As a result, refrigerant is sufficiently restricted from leaking into air from the pipe connection portion, while a blister is restricted from being formed in the first and second leakage restriction members.